My Programming Weblog

How to kill defunct process

Defunct processes are corrupted processes that can no longer communicate between the parent and child one. Sometimes, they become “zombies” and remain in your system until you reboot your machine. You can try to apply “kill -9” command, but most of the time you’ll be out of luck.

In order to kill theses defunct processes, you have two choices:
1. Reboot your computer
2. Continue reading…

This means you have 6 defunct processes: 3 of mono, and 3 of ruby. These processes exists because of poorly written application or unusual action taken by the user, in my case there must be some serious problem with the program I wrote in mono C# 🙂

If you try to kill the process with ID 8328 with the command “kill -9 8328”, it may not work. To properly kill it, you need to execute the kill command on its parent whose ID is 6757 ($kill -9 6757). Continue applying the kill command on all the PPID, and verify your result ($ps -A | grep defunct).

If the previous command display no result, well done, otherwise you may need to reboot your system.

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17 thoughts on “How to kill defunct process”

Patricksays:

Is there any way to kill a defunct process without killing its parent? I have a defunct python process that opens up every time I open Deluge (python bittorrent client), and killing Deluge stops the defunct process… until the next time I open Deluge.

I had the ruby defunct problem last week and the only solution we could find was to reboot, so thanks for your alternative solution.
Now, I would really appreciate if you could help with why does this defunct problem happens?

Patrick I don’t know how to kill the defunct processes without killing their parents. I tried that with no success.

Fernando Poblete I’m glad you found this post helpful. From my personal experience, some bad written program can cause create the defunct processes. In my case, I wrote a program using mono C# which created a lot threads. Because I was careless to take care of those threads when the main program is terminated, some of them are still alive.